how do I pair my fitbit to my blackberry z30

I don't have a Fitbit, but I have a Razer Nabu fitness band that has an Android app to sync with. First, you'll probably need at least BB10 10.3.2.x, which supports Bluetooth LE on the Android side. The procedure I usually do is this...

If you launch the Android app first or not wait 1-2 seconds, it's hit and miss for the Android app to see that Bluetooth is on. (Yes, if you launch the Android app, it'll tell you to turn on Bluetooth, but it's hit and miss for the connection.) If you wait longer than 1-2 seconds, there's a chance that the BB10-side will acquire the device before the Android-side and not allow the Android-side access to it. That's my experience.